Rolling machine element fatigue diagnosis method and rolling machine element fatigue diagnosis system

Abstract

A magnetic sensor arranged close to a component of a rolling machine element measures magnetic flux density in the axial direction and/or radial direction of the component, then the amount of change in magnetic flux density is calculated based on a reference magnetic flux density corresponding to the magnetic flux density before the start of use of the component, and the progression of fatigue of the rolling machine element is determined from the amount of change.

The invention claimed is: 
     
       1. A fatigue diagnosis method for a rolling machine element that diagnoses a state of progression of fatigue of a rolling machine element; the fatigue diagnosis method comprising
 a diagnosis step of diagnosing a fatigue state of the rolling machine element based on change in magnetic field information of the rolling machine element, wherein 
 the rolling machine element is a rolling bearing or a linear motion device comprising a component having a raceway surface made of a magnetic material, 
 the diagnosis step comprises a measurement step in which a magnetic sensor is arranged near the component and measures magnetic field information of the component, 
 the magnetic field information is magnetic flux density in an axial direction and a radial direction of the component, 
 the diagnosis step comprises a change amount calculation step that, based on a reference magnetic flux density corresponding to the magnetic flux density before the start of use of the component, calculates an amount of change in the magnetic flux density measured in the measurement step, and 
 the diagnosis step comprises a determination step that, using determination data that indicates a correlation between progression of fatigue of a test rolling machine element of the same kind as the rolling machine element that is found in advance by X-ray measurement using the test rolling machine element, and an amount of change in magnetic flux density in the axial direction and the radial direction of a component of the test rolling machine element of the same kind as the rolling machine element that is found in advance using the test rolling machine element, determines progression of fatigue of the rolling machine element based on the amount of change in the magnetic flux density calculated in the change amount calculation step. 
 
     
     
       2. The fatigue diagnosis method for a rolling machine element according to  claim 1 , wherein the reference magnetic flux density is a magnetic flux density of a portion of the component corresponding to a no-load area in a circumferential direction, or a magnetic flux density before use in a portion of the component corresponding to a load area in the circumferential direction; and magnetic flux density to be measured in the measurement step is magnetic flux density in a portion of the component corresponding to a load area in the circumferential direction. 
     
     
       3. The fatigue diagnosis method for a rolling machine element according to  claim 1 , further comprising
 a preparation step for finding the determination data; 
 the preparation step comprising:
 a first preparation step of finding an amount of change in magnetic flux density in an axial direction and/or radial direction of the component of the test rolling machine element before and after testing; 
 a second preparation step of finding progression of fatigue of the test rolling machine element after testing; and 
 a third preparation step of creating determination data indicating correlation between the progression of fatigue found in the second preparation step and the amount of change in magnetic flux density found in the first preparation step. 
 
 
     
     
       4. The fatigue diagnosis method for a rolling machine element according to  claim 1 , wherein the determination data is composed of a determination map in which progression of fatigue is mapped on a coordinate system having two axes that are the amount of change in magnetic flux density in the axial direction and the amount of change in magnetic flux density in the radial direction. 
     
     
       5. The fatigue diagnosis method for a rolling machine element according to  claim 1  that performs diagnosis without having to disassemble the rolling machine element. 
     
     
       6. A fatigue diagnosis system for a rolling machine element, comprising:
 a magnetic sensor capable of measuring magnetic flux density in an axial direction and/or radial direction of a component of a rolling machine element as a diagnosis target; 
 a calculating unit capable of calculating an amount of change in the magnetic flux density measured by the magnetic sensor based on a reference magnetic flux density corresponding to a magnetic flux density before starting use of the component; 
 a storage unit that stores determination data that indicates correlation between progression of fatigue of a test rolling machine element of the same kind as the rolling machine element that is found in advance by X-ray measurement using the test rolling machine element and an amount of change in magnetic flux density in an axial direction and/or radial direction of the component of the test rolling machine element that is found in advance using the test rolling machine element; and 
 a determining unit that determines progression of fatigue of the rolling machine element from the amount of change in magnetic flux density calculated by the calculating unit based on the determination data stored in the storage unit.